Spinal cord injury (SCI) disrupts the nerves controlling movement, along with those that
regulate functions like heart rate and blood pressure (known as the autonomic nervous system,
or ANS). Testosterone (T) plays a significant role in brain health and ANS reflex function in
non-neurologically impaired men. However, little is known about the relationships between T,
nerve function, and ANS dysfunction after SCI. Interestingly, up to 60% of men with SCI
exhibit persistently low T concentrations, which may worsen nerve and ANS dysfunction. In
uninjured eugonadal people (normal physiologic range of serum T concentrations), a single
pharmacologic dose of intranasal T has been shown to quickly improve nerve function, but no
study has evaluated if T administration alters nerve and ANS function in men with SCI.
Herein, the investigators will conduct the first study to test how a single dose of
intranasal T impacts motor and ANS function in this population.